To obtain optimum operation of an optical link, it is necessary for optical fiber ends to be prepared. A conventional way of doing this consists in providing a plane surface perpendicular to the axis of the fiber by means of a cutting device. When two fibers are placed end to end, these two plane surfaces are brought into coincidence and they produce reflections that may degrade transmission characteristics. A known way of remedying this defect is to provide the end of each fiber with a plane surface that is not exactly perpendicular to the axis of the fiber, with the normal of the plane being at an angle of 5 degrees to the fiber axis, for example. A known way of making such a plane surface is to cut the fiber in a section plane perpendicular to its axis by means of a conventional cutting tool and then to polish the section plane in such a manner that the resulting surface is inclined, e.g. at 5 degrees to the axis of the fiber. This method is complicated to implement, particularly under on-site conditions.
Japanese patent application No. 57-24903 describes a method of cutting an optical fiber obliquely, which method consists in holding the optical fiber at two points by means of two clamps, in twisting the fiber, in tensioning the fiber by applying a convex anvil thereagainst, after which cleavage is initiated by means of a diamond cutter. A smooth cutting plane is obtained at an angle of inclination which is a function of the torsion and of the tension applied to the fiber. However, there is no device on the market suitable for implementing this method or a similar method to cut an optical fiber obliquely under on-site conditions and with reproducible accuracy of within 1.degree..
An object of the invention is to provide a device enabling an optical fiber to be cut obliquely in a section plane at an angle that is reproducibly predetermined to an accuracy of within 1.degree. and over a temperature range of 0.degree. C. to 40.degree. C., which device should be simple to use, robust, and cheap.